Alameda County Registrar of Voters Dave Macdonald said today that they may not be able to announce who won the mayoral race until later this week, possibly as late as Friday. The registrar is still counting provisional ballots.

Oakland Councilwoman Jean Quan currently leads State Sen. Don Perata by 1876 votes, about 1% of the vote. This marks a stunning comeback for Quan, who was losing to Perata by 11% after the first round of voting, before Oakland’s ranked-choice voting system was put through its paces.

Alameda County Registrar of Voters Dave Macdonald said today that ballot counting for the City of Oakland elections will not be completed by this afternoon, as previously indicated.

“We still have a relatively small number of provisional ballots that are taking a little longer to process than expected,’’ he said.

The Alameda County Registrar of Voters Office – in agreement with the City of Oakland – has decided NOT to run the Ranked-Choice Voting algorithm in its release of the latest election results this afternoon.

The algorithm factors second- and third-choice votes into the ballot count in races where no candidate receives a majority of first-choice votes. The updated election results to be released this afternoon will reflect only first-choice votes.

The results will be updated – factoring in second- and third-choice votes – as soon as all ballots have been counted.

For now Jean Quan and her supporters are still optimistic that she will be the next mayor, KQED’s Tara Siler reports from Oakland City Hall.

(The 11 percent) gap prompted pollster David Latterman to tell the San Francisco Chronicle that “mathematically, she [Quan] just can’t do it.” Well, a little math never got in the way of a stunning political upset, and according to another expert we consulted, Quan’s surge is an entirely plausible — if unusual — consequence of Alameda County’s adoption of ranked choice voting.

Steven Hill, a consultant who was instrumental in setting up RCV in both San Francisco and Alameda County, said Quan’s chances of coming from behind — after a first round of vote-tallying had her with 24 percent of the vote to Perata’s 35 percent — were certainly low. “It was tough, for sure,” Hill says.